1. Field of the Invention
This invention relates to zone-controlled registers. In one of its aspects, the invention relates to an air register in which a thermally responsive motor linearly drives damper blades in an air register to control the flow of treated air in accordance with the temperature of the air in the room.
2. State of the Prior Art
Zone-controlled registers are devices which control the flow of heated or cooled air into a room independent of the thermostatic setting for a building to adjust the flow of air for the effects of sunlight, wind, people and other exterior effects on the building. These devices have been known for years but have apparently not been widely used. More recently, with the dramatic increase in fuel prices, the use of these devices has become more attractive to save energy.
Examples of thermostatically controlled ventilators are disclosed in the following U.S. Pat. Nos.:
Copping U.S. Pat. No. 2,523,497, issued Sept. 26, 1950;
Copping U.S. Pat. No. 2,523,498, issued Sept. 26, 1950;
Copping U.S. Pat. No. 2,523,499, issued Sept. 26, 1950;
Copping U.S. Pat. No. 2,628,032, issued Feb. 10, 1953;
Chace U.S. Pat. No. 2,749,044, issued Jun. 5, 1956.
In each of the devices in the above-enumerated patents, a shutter element is pivotably mounted in an air register which directs air principally in a horizontal direction into a room from a horizontal duct. A shutter is pivotably mounted on a pair of twisted wires at one end to apply a torque to the shutter tending to close the shutter. A thermally responsive actuator is mounted on the side of the register and is connected to the pivotable mounting of the shutter so as to reduce the torque created by the twisted wires and thereby oppose the torsional force of the wires. The actuator is provided in an opening and air is aspirated into the register over the actuator so that the actuator senses the room temperature rather than the temperature of the treated air passing through the register. Heating of the actuator reduces the torsional force applied to the shutter and thereby closes the shutter. Closing of the shutter must take place against the pressure of the air passing through the register and against the frictional forces present in the system. With the frictional forces and air-flow resistance, the balancing of the forces between the actuator and the wire at the axis of rotation may result in a significant lack of sensitivity of this device.
Other types of actuators for registers have used vapor-filled bellows mechanically connected to a linearly movable shutter and to a pivotably mounted shutter. See, for example, Newton U.S. Pat. No. 2,537,315, issued Jan. 9, 1951, and Peple, Jr. U.S. Pat. No. 2,701,101, issued Feb. 1, 1955. The mechanical advantage of the bellows mechanism is not significant and it may therefore be difficult to overcome the frictional and air-resistant forces with this type of mechanism to provide sufficient sensitivity for operation of the damper mechanism.
In all of the zone-controlled registers discussed above, the operating mechanisms appear to be fairly complex and would also appear to lack sufficient positive available force so that the register is relatively sensitive to relatively small changes in temperature.
Wax motors are recognized as forceful actuators which have been used to control fluid valves (McKee U.S. Pat. No. 1,884,794, issued Oct. 25, 1932), and to control ventilation system actuators (Marks et al U.S. Pat. No. 4,055,954, issued Nov. 1, 1977). These actuators are recognized to exhibit a significant linear force.
A common form of ventilation system uses a simple housing placed on a floor adjacent to a wall and distributes heated air from a duct extending to the floor upwardly into the room through louvers in the front face of the register. A vane is pivotably mounted in the front panel and has an exterior manual handle to control the flow of air through the louvers. It is desired to have a temperature control in this type of simple housing using relatively simple, yet reliable actuator elements. Such a system could be used to retrofit existing systems as well as for new construction.